This application is a continuation of international patent application no. PCT/EP01/03298, filed Mar. 23, 2001, designating the United States of America and published in German as WO 01/96729, the entire disclosure of which is incorporated herein by reference. Priority is claimed based on Federal Republic of Germany patent application no. DE 100 28 956.8, filed Jun. 16, 2000.
The present invention relates to an air filtration system comprising a system plate, a filter chamber having an air intake and an air outlet, and a filter element sealingly arranged in the filter chamber between the air intake and the air outlet so that air entering through the intake must pass through the filter element to reach the air outlet, in which the filter element divides an unfiltered air zone from a filtered air zone.
An intake module for an internal combustion engine, which comprises a plurality of integrated components, such as an unfiltered air intake opening, an unfiltered air intake passage, an air filter, a filtered air passage, and a filtered air connecting piece, is known from German patent application no. DE 198 02 074. The intake module is dimensioned in such a way that it completely covers the internal combustion engine. For this purpose, a flat plate is provided, which has shaped connection contours on its bottom side. A bottom part is attached to the bottom side of the plate, which is set on the connection contours and connected to the plate using multiple screws. To provide a sealed connection between the plate and the bottom part, a seal is inserted between the plate and the bottom part. However, screwing the top part onto the bottom part, and the insertion of the seal, results in high costs for materials and for assembly. Furthermore, the plate is a very complicated component, which is therefore difficult to manufacture due to the shaped connection contours.
The object of the present invention is therefore to provide an improved air filtration system for an internal combustion engine.
Another object of the invention is to provide an air filtration system which can be produced easily with low expenditures for materials and for assembly.
These and other objects are achieved in accordance with the present invention by providing an air filtration system comprising a system plate, a filter chamber having an air intake and an air outlet, and a filter element sealingly arranged in the filter chamber between the air intake and the air outlet so that air entering through the intake must pass through the filter element to reach the air outlet, the filter element dividing an unfiltered air zone from a filtered air zone; the system plate having upper and lower sides and at least partially covering a device; wherein the unfiltered air zone is formed by a first half shell permanently and sealingly attached to the system plate; and the filter chamber is formed by a filter housing attached to the system plate.
The air filtration system according to the present invention comprises a system plate having a top side and a bottom side, which at least partially, and preferably completely, covers a device such as an internal combustion engine. Furthermore, the air filtration system includes an unfiltered air intake and an unfiltered air zone, which discharges into a filter chamber. Positioned in the filter chamber is a filter element, which sealingly separates the unfiltered air zone from a filtered air zone having a filtered air outlet. The filter element has a peripheral seal and may be formed, for example, by a filter paper, preferably folded in a zigzag shape, or by a nonwoven filter web. In certain embodiments, the top side of the system plate may be designed as a visually appealing cover plate, and the bottom side of the system plate as function-oriented.
The unfiltered air intake discharges into the unfiltered air zone, which is formed by a first half shell in combination with the system plate. The first half shell is connected in a sealed manner to the bottom side of the system plate, thereby defining the unfiltered air zone. In some regions, particularly in the region of the unfiltered air intake, the first half shell may form a closed channel, so that the unfiltered air intake may, for example, be raised above the system plate. The connection of the first half shell to the bottom side of the system plate is a permanent bond which may be produced thermally or chemically, for example, by bonding with an adhesive. In this case, the use of an additional seal is not necessary, since the bond itself forms a seal. The sealing is performed, for example, by the adhesive applied. Mechanical attachment devices and seals thus may be omitted as a result of the permanent bonding of the system plate to the first half shell.
The filter chamber is formed by a filter housing which is attached to the system plate. In this case, for example, the filter housing may be a closed filter housing having openings which allow unfiltered air to enter the filter chamber and filtered air to exit. One side of the housing is then rigidly connected to the system plate. The opening in the filter housing for admitting the unfiltered air may be connected either detachably or permanently to the first half shell, which encloses the unfiltered air zone.
The filtered air zone is connected on the downstream side of the filter element to the filter chamber. It may be connected, for example, exclusively to the filter housing and not have any contact to the system plate. In this case, the filtered air zone may be designed, for example, as a connecting piece, having any desired cross-section, which extends directly from the filter housing.
According to a further embodiment of the present invention, the filtered air zone is formed by a second half shell in combination with the system plate. In this case, the second half shell may be attached to the filter housing or constructed in one piece therewith and may adjoin the opening for the filtered air in the filter housing or correspond to the downstream filter chamber through exclusive contact to the system plate, so that the filtered air flows through an opening in the system plate to the filtered air outlet. In this embodiment, the opening for the filtered air is positioned on the filter housing in such a way that it is located on the side connected to the system plate and covers the passage in the system plate. The second half shell may be positioned on the top side of the system plate, so that the filtered air may be conducted along the top side of the system plate. Through this design, diverse types of air guide variants are possible, which may be constructed in a very tight space.
If the second half shell adjoins both the filter housing and the bottom side of the system plate, the opening for the filtered air in the filter housing must be positioned in such a way that it discharges into the second half shell. Various types of air guidance possibilities may thus be constructed, in which both the unfiltered air inlet and the filtered air outlet are arranged on the bottom side of the system plate.
It is advantageous to permanently affix the filter housing to the system plate. For this purpose, thermal or chemical bonding methods may be used for the permanent attachment between the filter housing and the system plate. The bond between the system plate and the filter housing may be produced using the same bonding method as the bond between the first half shell and the system plate. Therefore, the first half shell and the filter housing may be bonded to the system plate in one work step, which saves time during assembly of the air filtration system.
In one specific embodiment of the present invention, the permanent bond is a weld seam. This weld seam may be produced, for example, using vibration welding methods or ultrasound welding methods. During such welding of the components to one another, material is melted, which forms a weld seam. Tolerances may thus be compensated, so that a sealed joint may be produced rapidly and reliably at a low assembly cost.
According to a further embodiment, the filter housing is formed by a housing frame, having a housing cover, and the system plate. The housing frame is welded to the bottom side of the system plate. Consequently, the bottom side of the system plate forms a part of the filter housing. The housing cover is sealingly attached in an air-tight manner to the housing frame, so that no air may escape from the filter housing or enter the filter housing. Sealing means, in particular rubber seals, may be provided for the sealed joint between the housing frame and the housing cover. Furthermore, the housing cover may be removably affixed to the filter frame, so that the filter element disposed in the filter housing may be replaced as necessary. In advantageous embodiments, the filter housing may be snapped removably onto the housing frame, so that the housing cover is rapidly and easily removable from the housing frame.
It is advantageous to dispose ribs on the system plate. In order to optimize the connection between the system plate and the first half shell, ribs, which may in particular be designed as narrow, flat ribs, may be provided on the bottom side of the system plate. The ribs may be straight or curved, and in certain embodiments they may follow the contour of the components connected to the system plate. As a result of the formation of the ribs, the system plate is provided with additional material, which may be melted during welding, for example, or which offers an additional contact surface during adhesive bonding. In addition, these ribs also increase the intrinsic stability of the system plate.
According to one advantageous embodiment of the present invention, the unfiltered air zone has an acoustically effective, curved air guide. In this case, the first half shell, which encloses the unfiltered air zone, is constructed in such a way that its course forms a curved air guide having desired acoustic effects. Multiple curved air guides, which positively influence the noise generated by the air flowing through the system, may also be provided in order to produce either a reduction in noise or a change in the emitted sound frequency which is generated. An omega curve represents an especially advantageous embodiment of the curved air guide.
In a further embodiment of the present invention, the unfiltered air zone has a second unfiltered air inlet, which may be opened using a flap. In this embodiment, the first half shell may be constructed in such a way that it also forms the second unfiltered air inlet. In this case, the flap is positioned in the first half shell in such a way that it may close off either the first unfiltered air inlet or the second unfiltered air inlet as a result of appropriate switch settings. In addition, a switch setting is conceivable in which the flap at least partially enables or opens both unfiltered air inlets. The flap is preferably positioned in the region where the unfiltered air zone which extends from the first unfiltered air inlet meets the unfiltered air zone which extends from the second unfiltered air inlet. In other embodiments, two separate flaps may also be provided, a first flap for closing off the first unfiltered air inlet and a second flap being used to close the second unfiltered air inlet. The two flaps advantageously have a connection which controls the flaps in mutual dependence on one another. By using a second unfiltered air inlet which may be opened, air may be drawn in from different surroundings. This is particularly advantageous in motor vehicles, since if the first unfiltered air inlet comes into contact with water or snow, for example, the flap may seal this unfiltered air inlet and open the second unfiltered air inlet, so that, for example, warmed air may be drawn in from the motor compartment, and the internal combustion engine may operate without danger.
A further embodiment provides attachment points for mounting the air filtration system on an adjacent internal combustion engine. The attachment points may be positioned on the system plate or on the components connected to the system plate. The attachment points may be formed directly on the system plate or on the components, or they may be constructed as separate components, particularly components made of rubber. Multiple attachment points are preferably provided distributed over the air filtration system. If the attachment points are constructed as separate components, in addition to the attachment function, they may also serve as oscillation dampers or as spacers between the internal combustion engine and the air filtration system, so that the air filtration system is not subjected to excessive mechanical or thermal loads.
In one advantageous embodiment of the present invention, the half shells and the system plate are made of a thermoplastic synthetic resin material. Therefore, the individual components of the air filtration systems may be produced easily and rapidly using injection molding, and the components may be assembled, for example, using friction welding. In addition, the air filtration system may be easily disposed of or recycled after use.
These and other features of preferred embodiments of the invention, in addition to being set forth in the claims, are also disclosed in the specification and/or the drawings, and the individual features each may be constructed in embodiments of the invention either alone or in the form of subcombinations of two or more features and can be applied to other fields of use and may constitute advantageous, separately protectable constructions for which protection is also claimed.